1. Field of the Invention
This invention relates to a fillable sample taking vessel for handling a liquid sample, particularly a vessel for use as a pipette tip, which vessel has an opening which is relatively large in cross-section at one end, where the vessel is relatively large in diameter, and tapers in conical shape to the other end and is formed there with an intake and discharge opening (to be described as an intake opening hereinafter), wherein a movable valve member for sealing the intake opening is provided adjacent to the intake opening and is provided with an actuating rod, which protrudes out through the intake opening and is bare relative to the intake opening.
In a special embodiment the invention includes a sample taking vessel in which the opening which is relatively large in cross-section is defined by a cylindrical wall portion and in which a piston which has been inserted through the relatively large opening has an outwardly extending piston rod, and which sample taking vessel is optionally provided with a flange at the end which is relatively large in cross-section.
In that context the invention provides also a process of handling a liquid sample in a sample taking vessel which is conical at least in part and has a tip that is provided with an opening which constitutes an intake opening or also a discharge opening.
2. Description of the Prior Art
A fillable sample taking vessel of the kind described hereinbefore is known from Published German Application No. 30 29 718. For the transport of liquids to be analyzed, that sample vessel can be sealed at its bottom after the liquid has been sucked into the vessel. It is intended to seal the vessel by an operation performed with one hand. For this reason the known embodiment comprises the downwardly protruding actuating rod.
In the embodiment comprising a movable valve member a valve seat is provided within the vessel close to the intake opening and the valve member can be seated on that valve seat in that the actuating rod is forced against an abutment. As a result, the valve member is non-detachably connected to the valve seat for the further manipulation and/or an irreversible snap-action joint is established so that the filled sample vessel is sealed at its bottom as it is transferred to a different location and no liquid can escape even when the suction has been discontinued.
When the bottom intake opening has been sealed and liquid is subsequently to be dispensed, it will be necessary to detach the sample vessel from a pipette or a similar device, depending on the embodiment, and to take out or pour the liquid from the top. That operation is time-consuming and complicated and a satisfactory operation requires special skill and time. That known embodiment has mainly been provided in order to reliably hold in the sample vessel a liquid which has been received by the vessel.
It is known to provide valves on pipettes rather than on sample vessels which can be fitted on pipettes. German Patent Publication No. 22 29 623 discloses a valve and a throttling bore in the pipette, specifically in a special guide piece, in order to provide an air duct for retarding the upward movement of the piston of the pipette so that the sample vessel proper will be filled uniformly and without splashing. That arrangement has the object to provide a particularly simple pipette, which can infinitely and linearly be adjusted to various volumes and can be calibrated also for various liquids. The so-called fit-on pipette tube, which is comparable to the sample vessel, is provided in the usual manner without any additional features.
In accordance with Published German Application No. 26 58 592 a pipette for mixing a liquid with another liquid, which has been taken up by a pipetting action, is provided with valve means for controlling the intake of liquid and for contacting the two liquids with each other.
Those valve means are contained in a special pipette, which has a complicated design, rather than in a sample taking vessel, and is not related to a valve for controlling an intake opening of a sample taking or fit-on vessel or a tiplike vessel assembly, which is provided with a piston.